Dry rectifier



March 28, 1944. H. HERRMANN DRY RECTIFIER Filed Oct. 23, 1940 ORNE Y .base plate electrode I,

Patented Mar. 28, 1944 OFFICE DRY RECTIFIER Heinrich Herrmann,

vested in the Alien Nuremberg,

Property Custodian Germany;

Application october 2s, 1940, sei-131m. 362.462 In Germany: October 17, 1939 7 Claims.

This invention relates to rectiners of the l-nind comprising so-called valve discs and consists in certain features of novelty which will appear from the following description, reference being had to the accompanying drawing, in which Fig. 1 is a fragmentary sectional view of a discs represented in Fiig. 2.

For the sake of clearness the plates and layers constituting the valve discs are shown larger in thickness than they really are. f

The valve discs represented in Figs. 1 and 2 are in well-known manner each composed of a a semi-conductor layer 3 carried by plate I,the so-called counterelectrode 5, produced by spraying metal against layer 3, and layer 'I that forms between the layers 3, 5 during the manufacture of the These rectifying valve discs I, 3, 'I, 5 have each a central lbore 2 provided in the plate I. The bores 2 are to receive a mandrel and an insulating tube 9 inserted over this spindle. The valve discs are serially mounted on the mandrel 8, 9.

The prior arrangement illustrated in Fig. 1 has insulating discs Ill and resilient contact plates II likewise mounted on the mandrel 8, 9 and disposed between the valve discs. 'Ihe plates II are arranged to contact with the trodes 5 and base plate electrodes I bear against the layers 3 and plates II and are surrounded by the counterelectrodes 5. They are thick enough to provide for cooling interspaces I2 between the valve discs.

The arrows in la means of the 2, namely, nut screws I3 on mandrel 8, 9 to contact each with one of the 65 sp aying, has raised (ci. 17a-ass) f extensions A trode I,

and the adjacent provided between the valve discs. The extensions A are separated from the layers 3 by annular insulating means which preferably are constituted by a lacquer coating 4 on the layers 3. 'I'he valve discs are 4pressed together by the nut screws I3 of spindle-8. The coatings 4 prevent the plates sprayed against layer 3 might fbe able to interconnect the parts I, 5, thus short-circuiting the blocking layer 'I also in this case.

The lacquer coating 4 may be 3 by stamping or rolling or method.

applied to layer any other suitable According to Fig. 3 the lacquer coating 4 may be produced as follows.

layer 3 metal is sprayed to form a layer 5' which striking the coating I5 acts to destr it at where layer 5', being produced by dipping or On the semi-conductor the layer 5" will hence contact with layer 6' and thus constitute a counter-electrode 5', 5 equivalent to that designated 5 in Fig. 2. vin order t'o give a pictorial idea of this the dotted line in Fig. 3 represents by way oi example the surface o1' the coating I5 before the layer 5" is produced on it.

What is claimed is: l

l. The method of manufacturing a valve disc which comprises spraying a metallic material onto a semi-conductor layer except for a central area thereof, so as to produce an annular metal layer on the semi-conductor layer, providing such metal layer and said area with a lacquer coating, that part of the lacquer coating which is applied t0 this area constituting an insulating means, and spraying a metallic material onto such lacquer coating so as to form a metal layer thereon and to destroy the lacquer coating in part, whereby the two said metal layers contact with each other through-the lacquer coating, thus constituting the said counterelectrode.

2. The method of manufacturing a va1ve disc in which the semi-conductor layer is of selenium while the insulating means is a lacquer coating, which method comprises applying this lacquer coating to an amorphous selenium layer and then heating the assembly composed -of a .base plate electrode, selenium layer and lacquer coating to the forming temperature of selenium.

3. The method of manufacturing a valve disc in which the semi-conductor layer is of selenium while the insulating means is a lacquer coating, which method comprises the step of heating the assembly composed of a base plate electrode and 35 selenium layer to a preliminary forming temperature of selenium, applying the said lacquer coating to the selenium layer, and heating the assembly composed of the base plate electrode, selenium layer and lacquer coating to the forming 'temperature of selenium.

4. A rectifier comprising a base plate, a semiconductor layer carried by the base plate, a first sprayed metal layer placed over an outer portion of the semi-conductor layer, an insulating layer over the central portion of said semi-conductor layer and extending in a thin coating over said sprayed metal layer, and a second sprayed metal layer over said thin insulating coating and making contact with the first-mentioned sprayed metal layer.

5. A rectier according to claim 4 in which the ilrst and second sprayed metal layers make contact with each other at minute points through the thin insulating coating.

6. A rectifier according to claim 4 in which a blocking layer is formed between said semiconductor layer and the first sprayed metal layer.

7. A rectifier comprising a base plate, a se lenium layer. carried by the base plate, a central portion of said selenium layer being covered by a disc of insulating material, a portion of said selenium layer not covered by said disc being covered by a blocking layer, a sprayed metal layer covering said blocking layer, an insulating illm over said metal layer, and a second metal layer covering said lm and said insulating disc, said metal layers making contact with each other at minute points through the insulating lm.

HEINRICH HERRMANN. 

